We have a team called "general". In this channel there should be all of our employees.Let´s say our company gets 2 new employees. Both of them will be in the active directory group "employees". Is it possible that they will be automatically added to the team "general"?

Okay thanks. I wanted to try this out now. Unfortunately I don´t get the membership type "Dynamic User" or the "Dynamic membership rules" that are described in your first link.Am I doing something wrong?

Every mailbox has 15 customizable attributes that you can use for your own purposes. Here's how to update a mailbox using CustomAttribute1 with a value that you can later check.

Set-Mailbox -Id Someone -CustomAttribute "Y"

To find all mailboxes that do not have the attribute set:

$Mbx = (Get-Mailbox -Filter {CustomAttribute1 -ne "Y"})

Now process each mailbox and add them to the Office 365 Group (you could also use Add-TeamUser but this is easier because it saves loading a module). Then also update the mailbox so we don't process it again.

ForEach ($M in $Mbx) {

Add-UnifiedGroupLinks -Id MyGroup -LinkType Members -Links $M.Alias

Set-Mailbox -Id $M.Alias -CustomAttribute1 "Y"

}

If you're getting into this kind of stuff, perhaps you should buy a good book that discusses how to use PowerShell with Groups and Teams. Like Office 365 for IT Pros (which I am involved in).

Looks like Cayosoft has recently (Dec 2018) eliminated their <200 users-for-free option - their tool does a great job for Teams, AD and exchange mgmt without Powershell, but pricing more realistic for the 500+ companies.

Thanks for the info.". If your environment has 100 users or less you can request a free subscription license for our commercial tools so you can use all of the features at no charge"It's new price table. https://www.cayosoft.com/free-office-365-tools/